The art of locating and measuring aspects various objects can be cumbersome, usually involves multiple steps with multiple tools that require the use of both hands, and for some measurements, can be very difficult. The art of locating the center of a circle has been greatly simplified to be a one-handed single step operation by the current invention. It would be of great benefit to provide similar simplifications for how to measure, locate, and draw other aspects of objects as well. Particular areas of need are: measure the size of a circle, distance between two points, depth of a cavity, and the angle between two lines; locate the midpoint between two points, and draw a circle of a desired size.
Perhaps the most common method to determine the size of a circle is to first accurately determine the diameter of the circle. One may use a compass and a ruler by draw intersecting arcs on the circle and drawing a straight line with the ruler between the intersections to create a diameter line that can then be measured. A center finding tool, such as the combination square that consists of a 90 degree angle portion and straight edge configured to hold the straight edge along the diameter of the circle when 90 degree portion is held against the circle edge, may also be used to find the diameter of a circle. With both of these methods however, one must then measure the length of the diameter to determine the size of the circle. These common methods require the use of multiple tools and require multiple steps.
For measuring the angle between two lines, a protractor is the most common tool. The typical method to measure the angle between two lines is by use of a protractor. In certain cases, a ruler must also be used to draw additional line extensions to complete the measurement. The method is a three step process: a) place the base of the protractor along the first line, b) slide the protractor along the line until the center point of the protractor is at the intersection of the second line and, c) read where the second line intersects the scale on the protractor. If the lines do not intersect, some means of extending or projecting the lines to their point of intersection must be used. In many cases, the means can be a ruler placed co-linear with one of the lines where an extension can be drawn to the other line creating the point of intersection. The state of the art has been advanced by Liu, U.S. Pat. No. 4,766,675 which resolves a majority of the non-intersecting line situation as the apparatus relies on co-linearly aligning both lines such that the point of intersection is not required to determine the angle between the lines. While an improvement to the state of the art, the Liu apparatus generally requires two hands for operation. In the most recent state of the art, Figliuzzi, U.S. Pat. No. 6,076,270, also resolves the non-intersection problem and does so with an apparatus that hingedly connects vertical plates with a frame that allows one handed operation to measure angles.
For many purposes, locating the midpoint between two points is more useful than measuring the distance between the points. For instance, there is great need to fold, cut, or divide something in half. The most common method used typically requires four steps: a) measure the distance across the item to be folded, cut, or divided, with a ruler, b) manually calculate half of that distance, c) locate the new halved distance on the ruler, and d) mark the half point of the item. In addition to being cumbersome and time consuming to complete four steps, the step of calculating the half distance becomes particularly difficult when the distance across the item has a fractional component. Calculating the half distance in this case requires complicated fractional division.